Shift mechanism

ABSTRACT

A type element of a single element printer is shifted to print upper or lower case type characters by a crank which is rotatably driven through 180* with each actuation of a shift key to pivot a shifting lever of a mechanism for rotating the type element. The crank is connected to the shifting lever by means of a tape which is drawn around a roller of a pivotal guide arm and secured to a slide member mounted on a pin of the crank which extends through an elongated slot in the guide arm. The crank is rotatably driven by a drive mechanism coupled to a power roll by a half-turn clutch, and a detent arrangement is provided to accurately position the crank at rotational positions spaced 180* apart.

United States Patent 1191 11 1 3,842,958

Link 1 Oct. 22, 1974 [5 SHIFT MECHANISM 3.5l6,528 6/1970 Davidge el al197/16 [75] Inventor: Manfred Link, Nuernberg, Germany 3s8]86O 6H9.Schaefer X [73] Assignee: Triumph Werke Nuernberg A.G., PrimaryExaminer-Robert E. Pulfrey Nuernberg, Germany Assistant Examiner-R. T.Rader [22] Filed y 30 1973 Attorney, Agent, or Firm-Joseph R. Spalla[21] Appl. No.: 365,253 [57] ABSTRACT A type element of a single elementprinter is shifted to [30] Foreign Application Pri -fly Dat print upperor lower case type characters by a crank July 6 1972 Germany 223369which is rotatably driven through 180 with each actuation of a shift keyto pivot a shifting lever of a mecha- [52] US. Cl. 1. 197/18 forrotating type elemem' The crank is 511 1111. C1 B4lj 23/04 "actedShifting ever by means a taPe which [58] Field of Search U 197/16 7 1848 49 is drawn around a roller of a pivotal guide arm and secured to aslide member mounted on a pin of the crank which extends through anelongated slot in the [56} References cued guide arm. The crank isrotatably driven by a drive mechanism coupled to a power roll by ahalf-turn UNITED STATES PATENTS clutch, and a detent arrangement isprovided to accu- 2,989,l66 6/1961 Walker et a]. t. l97/l6 ratelyposition the crank at rotational positions spaced 3,227,259 l/l966Howard l97/49 I809 apart 3,228,510 1/1966 Howard 197/49 3,467,233 9/1969.Iablowski .1. 197/16 4 Claims, 1 Drawing Figure SHIFT MECHANISM Thisinvention relates to a single element typewriter, and more particularlyto a shift mechanism for shifting a type element to print upper case orlower case type characters.

in a single element typewriter, a plurality of type characters arelocated at different positions on a type element, and the printing of aselected type character is effected by orienting the type element toimpact the desired type character against the platen. As isconventional, both lower and upper case type characters are arranged ondifferent portions of the type element with the printing ofcorresponding type characters being controlled by common type keymechanisms. Upon op eration of the type key mechanisms, type charactersare selected from whichever group of type characters are presented forprinting, and the printing may be shifted to another group of typecharacters by rotating the type element to present the other group forprintmg.

Typically, the print element is rotated in response to the movement ofan associated drive member which is moved by means of a tape upon theoperation of either a character selecting mechanism or a shiftingmechanism. Such an arrangement is shown for example, in U.S. Pat. Nos.2,897,876 and 3,077,971, and it is essential that the shifting beeffected quickly between exactly defined positions. Moreover, it isdesirable that the shifting movement have a sine-shaped characteris ticto quickly bring the moving members to rest.

Accordingly, an object of the present invention is to provide a shiftingmechanism having a simple construction as well as a fast and reliableoperation.

Still other objects, features and advantages of the present inventionwill become apparent to those skilled in the art from a reading of thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawing, wherein the single FIG- URE showsdiagrammatically a single element printer having a shifting mechanismconstructed in accordance with the present invention.

Referring now in detail to the FIGURE in the drawing, there is shown asingle element printer, generally indicated 11, having a type element 13with a plurality of type characters 15 at different positions forprinting on a suitable recording medium, not shown. As is conventional,printing is effected by impacting the type element 13 against therecording medium which may be suitably supported on a platen, not shown,and the type element 13 is mounted on a carriage 17 for movement alongthe platen to print a line of type. The type element 13 is rotatablysupported on the carriage 17 by suitable means, not shown, and aselected type character 15 is printed by orienting the type element 13so that the desired type character 15 will be impacted against therecording medium. The rotational orienting movement of the typehead iseffected by a rotating means, generally indicated [9, which is actedupon by a type key mechanism, not shown, which controls the movement ofthe type element 13 to position the selected character 15 for printing.The plurality of type characters 15 includes both upper and lower casechar acters which are arranged on different portions of the type element13 with the type key mechanism controlling the printing of correspondingtype characters 15. The type key mechanisms select type characters 15from whichever group of type characters 15 is presented for printing,for example the lower case type character, and to print a type characterfrom the upper case type characters, the rotating means 19 is acted uponby a shifting mechanism, generally indicated 21, which may be controlledby a suitable shift key to effect l rotational movements of the typeelement to present the upper case type characters for printing. Therecording medium, the platen, the keyboard and the key actuatingmechanism as well as other portions of the printing aren't shown sincethey form no part of the invention and may be desirably conventional.

As shown, the type element 13 is carried by a spindle 23 having anattached wheel 25 which is acted upon by the rotating means 19 forenabling rotational move ment of the type element 13 at any position ofthe carriage along the platen. The rotating means 19 includes a tape 27drawn around pulleys 29, 31 at the opposite ends of the carriagemovement with one end of the tape 27 secured to the wheel 25 and theother end attached to the carriage 17. The pulleys 29, 31 are carried onthe ends of a pair of corresponding levers 33, 35 which may be pivotallysupported on opposite sides of the typewriter frame with the lever 35,hereinafter referred to as a shifting lever, being acted upon by theshifting mechanism 21 in a manner to be explained below, and with thelever 33 being connected to the type key mechanism by a suitable link37. The type key mechanism controls the orientation of the type element13 in a conventional manner by pivoting the lever 33 to pull on the tape27 and thus rotate the type element 13.

Since the printing of corresponding upper and lower case type characters15 is controlled by common type key mechanisms, the particular typecharacters 15 selected depends on which set of type characters 15 arepresented for printing. To change or shift the printing from lower toupper case type characters 15, the type element 13 is rotated and thisis accomplished by pivoting the shifting arm 35 to pull against the tape27 and rotate the type element. However, the shifting must be accurateand the shifting movement should desirably have a sine-shapedcharacteristic so as to bring the moving parts quickly to rest and avoidbacklash. As is conventional, the pivoting of the shifting lever 35 iseffected by a shifting mechanism 21 which is actuated by a suitableshift key which may be located on the keyboard area of the singleelement printer.

In accordance with the present invention, the shifting lever 35 ispivoted by a shifting mechanism 21 in the form of a shift crank,generally indicated 39, which is connected to the shifting lever 35 bymeans of a suitable band 41 and rotatably driven by drive means,generally indicated 43. As shown, the crank 39 is in the form of a crankplate 45 rotatably supported by a suitable shaft 47 and having a crankpin 49 spaced radially from the axis of rotation. The crank pin 49 isconnected to the shifting lever 35 by the band 41 having one end securedto the shifting lever 35 by a suitable adjustable connector 51 while theother end of the band 41 is secured to a slide member 53 which ismounted on the end of the crank pin 49 so as to pivot the shift lever 35in response to the rotational movement of the shift crank 39. To guidethe band from the shifting lever 35 to the crank pin 49, the band 41 isdrawn around a defleeting pulley 55 rotatably mounted on a guide arm 57which is pivotally supported and has an elongated slot 59 through whichthe crank pin 49 is received.

The shift crank 39 is rotatably driven by the drive means 43 whichincludes a drive gear 61 rotatably supported by a suitable shaft 63 andmeshing with the gear teeth 65 formed circumferentially on the crankplate 45. The drive gear is rotatably driven by a drive shaft 67 of apower roll 69 which is coupled to the drive gear 61, by a half-turnclutch 71 with each actuation of the shift key. The half-turn clutch 71may be desirably conventional and couples the drive shaft 67 to thedrive gear 61 for 180 of rotational movement, whereupon the half-turnclutch 71 discontinues the rotational drive. To accurately position thetype element 13 at the shifted positions, the crank plate 45 has aperipheral surface 73 with diametrically opposite detent notches 75 forreceiving a detent member in the form of a roller 77 carried on one endof a lever 79 and resiliently urged against the peripheral surface 73 byresilient biasing means in the form of a spring 81 stretched between thelever 79 and a suitable portion of the printer.

In operation, the type element 13 may be shifted from lower to uppercase characters by actuating a shift key to couple the drive gear 61 tothe drive shaft 67 by means of the half-turn clutch 71 for rotating theshift crank 39 through 180. As the crank plate 45 is rotatably driven,the detent roller 77 is removed from the detent notch 75 against theurging of the spring 81, while the crank pin 49 moves through theelongated slot 59 of the guide arm 57 to pivot the shifting lever 35.Upon completing the 180 of rotation, the drive gear 61 is disconnectedby the half-turn clutch 71 while the detent roller 77 is urged into thedetent notch 75 of the crank plate 45 thereby accurately positioning thetype element 13 with the upper case type characters 13 presented forprinting. Similarily, the type element 13 may be shifted to print thelower case type characters by again operating the half-turn clutch 71 torotate the crank plate 45 through 180, whereupon the crank pin 49 willmove along the elongated slot 59 in an opposite direction, therebyenabling the shift lever 35 to return to its previous position androtate the type element 13 to present the lower case type characters 15for printing.

What is claimed is:

1. In a single element typewriter having a type element with upper andlower case characters arranged on different portions and rotatable topresent the upper and lower case type characters for printing, androtating means including a shift lever pivotally movable for controllingthe rotation of the type element, the improvement comprising:

a shift crank supported for rotational movement,

a crank pin secured to said shift crank at a location radially spacedfrom the axis of rotation of said shift crank and extending therefrom inan axial direction, a band,

means connecting said band between the shift lever and the crank pin forpivoting the shift lever in response to the rotational movement of theshift crank, and

drive means operable with each actuation for rotating the shift cranksubstantially to rotate the type element to present a different case oftype characters for printing.

2. In a single element typewriter according to claim 1, said connectingmeans comprising:

a guide arm pivotally supported adjacent said shift crank with anelongated slot formed therein for receiving the crank pin and having adeflecting roller mounted thereon for guiding the band toward the crankpin, and

a slide member connecting the band to the crank pin and being slidablealong said guide arm in response to the rotational movement of saidshift crank.

3. In a single element typewriter according to claim said shift crankbeing in the form of a crank plate mounted on a rotatable shaft with thecrank pin being radially spaced from the axis of rotation of the crankplate,

said crank plate having a peripheral surface with detents formed thereinat 180 apart,

a detent member cooperable with said crank plate for engagement with thedetents formed in the periphery thereof, and

resilient biasing means urging said detent member into engagement withthe peripheral surface of said crank plate to bring said detent memberinto cooperating engagement with the detents of the crank plate to stopthe rotational movement thereof.

4. In a single element typewriter according to claim said shift crankbeing in the form of a crank plate mounted on a rotatable shaft with thecrank pin being radially spaced from the axis of rotation of the crankplate,

said crank plate having a peripheral surface with detents formed thereinat 180 apart,

a detent member cooperable with said crank plate for engagement with thedetents formed in the periphery thereof, and

resilient biasing means urging said detent member into engagement withthe peripheral surface of said crank plate to bring said detent memberinto cooperating engagement with the detents of the crank plate to stopthe rotational movement thereof. t 11 1F

1. In a single element typewriter having a type element with upper andlower case characters arranged on different portions and rotatable topresent the upper and lower case type characters for printing, androtating means including a shift lever pivotally movable for controllingthe rotation of the type element, the improvement comprising: a shiftcrank supported for rotational movement, a crank pin secured to saidshift crank at a location radially spaced from the axis of rotation ofsaid shift crank and extending therefrom in an axial direction, a band,means connecting said band between the shift lever and the crank pin forpivoting the shift lever in response to the rotational movement of theshift crank, and drive means operable with each actuation for rotatingthe shift crank substantially 180* to rotate the type element to presenta different case of type characters for printing.
 2. In a single elementtypewriter according to claim 1, said connecting means comprising: aguide arm pivotally supported adjacent said shift crank with anelongated slot formed therein for receiving the crank pin and having adeflecting roller mounted thereon for guiding the band toward the crankpin, and a slide member connecting the band to the crank pin and beingslidable along said guide arm in response to the rotational movement ofsaid shift crank.
 3. In a single element typewriter according to claim2: said shift crank being in the form of a crank plate mounted on arotatable shaft with the crank pin being radially spaced from the axisof rotation of the crank plate, said crank plate having a peripheralsurface with detents formed therein at 180* apart, a detent membercooperable with said crank plate for engagement with the detents formedin the periphery thereof, and resilient biasing means urging said detentmember into engagement with the peripheral surface of said crank plateto bring said detent member into cooperating engagement with the detentsof the crank plate to stop the rotational movement thereof.
 4. In asingle element typewriter according to claim 1: said shift crank beingin the form of a crank plate mounted on a rotatable shaft with the crankpin being radially spaced from the axis of rotation of the crank plate,said crank plate having a peripheral surface with detents formed thereinat 180* apart, a detent member cooperable with said crank plate forengagement with the detents formed in the periphery thereof, andresilient biasing means urging said detent member into engagement withthe peripheral surface of said crank plate to bring said detent memberinto cooperating engagement with the detents of the crank plate to stopthe rotational movement thereof.